Method of operating blast furnaces and similar furnaces



I Patented Sept. ,9, 1924.

UNITED STATES mmn B. IL'BBY, 01' NEW YORK, N. Y.

m!) 0] orm'rnm BLAST FURNACES AND SIMILAR FURNACES.

"Application fled Iebruary 18, 1920, Serial No. 858,969. Renewed July 14, 1984.

To all whom it mag concern:

Be it known that I, EDMUNQ B. Krnnr, a citizen of the United States, residing at New 'York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Methods of Operating Blast Furnaces and Similar Furnaces, of which the following is a full, clear, and exact description.

The present invention relates toa method or process applicable in the operation of blast furnaces, cupola furnaces or other furnaces of'similar nature and for similar purposes.

The objects of the invention and the results will appear more at large as the description proceeds.

Reference should be had to the accompanying drawings forming a part of this specification in which Fig. 1 is an elevation with portions in section of a furnace in which the process may be carried out; Fig. 2 is a transverse sectional elevation of such a furnace; Fig. 3 is a vertical transverse section through the outlet end of the base of the furnace; Fig. 4 is a horizontal section at the level of the lower row of tuyeres.

' As the description proceeds, reference will be made to the application of the method and process of a blast furnace, but this is done without intending any limitation as to the precise form of furnace which may be used.

Furthermore, in ex laining the process reference will be ma 0 to the application thereof to the production of pig iron from iron ore but in this instance also no intentional limitation is intended thereby.

In the operation of blast furnaces for various purposes and to produce various products, the material which is to be treated, such as a mixture of various ores with limestone and other fluxes is fed into the furnace together with coke.

The tuyeres of the blast furnace are located near its base and introduce a blast of air into the column of material and fuel. The combustion of the latter causes various chemical reactions and the fusion of the products.

In the usual operation of blast furnaces, the carbon burned at the tuyeres is oxidized only to carbon. monoxide liberating Only one-third of the total of the carbon.' Attempts to produce carbon dioxide meet with various practical difliculties, such as the dissociation of carbon dioxide, its reduction to carbon monoxide by the heated fuel above through which it rises, the necessity for havmg carbon monoxide act upon the 'ore for a certain time, etc. Y

In the process herein proposed, no attempt? I is made to restrict the natural formation of carbon monoxlde in the zone of combustion at the mam blast. In fact, for man cases,

the blast is so regulated as to prompt y form the maximum quantity.

The carbon monoxide, with such other gases as accompany it, is allowed to rise through the descending column and perform its chemical action uponthe heated material for the time required. Sup 1ementary introductions of blast are. t en made at the properlevel or succesion' of levels and these burn the carbon monoxide to carbon dioxide. This liberates the other two-thirds of the heat which is absorbed b the descending material'and conveyed bac down to the zone of fusion where the material arrives so preheated that its fusion is rapid. By means to 'be described, the carbon' dioxide escapes without reduction to carbon monoxide.

A'blast of oxygen or of air enriched with oxygen constitutes an important and often necessary means of performing the above operation. The increased'rapidity of fusion calls for the continuous discharge of molten products in a more satisfactory manner than is possible with present practice while another result flowing from the new method of operation is to make possible the use of fluid or pulverulent fuel when'this is desirable.

In carrying the invention into practice, the material and the solid fuel, suchas anthrac ite coal or coke, are fed in at the top of the furnaceso that they will descend as separate columns, each of the columns maintaining its'identity, but in contact each with the other. The solidfuel, prior to its being fed into the furnace, has been crushed to a size such that the interstices between the pieces of the fuel will be of much smaller average size than the interstices between the pieces of material making up the ma-' wajyi we umn more dense and less penetrable by the gases which pass upwardly through the furnace, and under the conditions named they will almost entirely ascend through the material column. Solid fuel, such as coke or anthracite does not readily agglomerate or sinter under heat but Will remain mobile and will thus descend uniformly and flow into irregularities caused by its combustion.

By referring to the drawings, 10 represents a fuel column such as coke and 11 represents the column of material, both being fed at the top of the furnace. The main blast is delivered by means of the tuyere 13 which communicates with the wind box 14.

As will be noted, the tuyere extends nearly through the coke column so that the blast is delivered within the coke mass suf -ficiently near its contact with the column of material for the heat and gases of combustion to escape from the fuel mass and act upon the column of material. It will be understood that while only one tuyere is shown in the drawing, there may be a plurality of such tnyeres used in actual practice.

The main blast located near the base of the furnace may be introduced in any way which will best enable it to reach and act upon the surface of the fuel column which is in contact with the column of material. Most materials as they approach fusion become pasty and sinter together in such a as to hinder or prevent the blast as as the current of ases of combustion from penetrating them. ite hot fuel such as coke has no adhesion to such pasty material while the interstices of the fuel mass although smaller than those of the material, remain open. These nonadherences and interstices therefore present a relatively easy and continuous by-path or channel wherein the blast and the gases of combustion may find their way past the pasty zone, beyond which zone the gases can readily esca e into the open and larger interstices o the column of material and so ascend.

For the reasons specified it is preferable and in most cases necessary to introduce the lower blast substantially at the surface of contact.

The lower tuyeres are made adjustable with respectto their position in the furnace so that the tuyeres may be properly positioned to discharge the blast in proper relation to the surface of contact between the column of material and the coke under varying positions of this surface, which stands in a curve of equilibrium depending upon the relative specific gravities of the two columns and other factors.

The main blast thus delivered causes the fusion of the material and produces gases of combustion carrying carbon largely or wholly in the form of carbon monoxide. These ases rise through the column of materia At a suitable point, above the lower tuyere there is a second blast introduced through an auxiliary tuyere, 'into the column of material as indicated at 15, and if desired an additional blast may be introduced or additional blasts as indicated at 15. These auxiliary tuyeres are positioned at a point above the main or lower tuyere far enough to give the carbon monoxide opportunity to remain in contact with the material through which it ascends, fora desired period of time, this being necessary to effect certain chemical reactions within the descending column.

When the carbon monoxide reaches the zone in which the auxiliary tuyeres are located, it is burned to carbon dioxide, which liberates the remaining heat incident to burning the carbon and this heat is absorbed by the descending column of material so that the aforesaid column is in highly heated condition when it reaches the zone of fusion.

The carbon dioxide which is formed at the auxiliary tuyeres, ascends through the column of material and is conducted away from the top of the furnace. This operation is made possible by the fact that the carbon dioxide ascends from the zone of the auxiliary tuyeres through the column of material and not through the fuel column due to the fact before stated that the gases find a more ready passage through the column of material than through the fuel column.

Due to the mobility of the descending fuel column the particles of fuel will flow around the tuyeres with which they c0ntact and to assist this the nozzles of the tuyeres stand in a downwardly slanting direction which also serves the urpose of preventing fine particles of fuel rom entering the tuyeres.

In the construction preferred for carrying out the process, this flow of fuel aids in protecting the water-cooled tuyeres and since crushed fuel is a non-conductor, the nozzle is protected from extreme heat by that portion of the fuel mass which intervenes between it and the contact surface.

In order to facilitate the action of the auxiliary tuyeres and to secure a thorough mixture of the blast introduced through these tuyeres, with the ascendin gases so as to induce complete combustion, it is desirable and in many cases may be necessary to use oxygen or air enriched with oxygen in the upper or the lower blast or in both.

In both blasts and particularly in the auxiliary one, it is very difiicult, within the interstices of the material, to secure the proper mixture and a prompt absorption. of the heat. This is due mainly to the great volume and velocity of the ascending gases owi to their excessive dilution with nitrogen om the air ordinarily used.

The abolition of nitrogen in whole or in part from the blast used will thus reduce the absorption height-of the column, concentrate both zones of .combustion and at both places provide a higher flame temperature which hastens the transfer of heat.

For the blast it is therefore, desirable to use oxygen which is pure or as nearly pure as is commercially practicable for the process which furnishes the oxygen supply.

In special cases, however, and temporarily whenever the furnace is .bein started or when its operation is resume after some interruption, I prefer to employ a blast which is not so fiercely oxidizing and whose oxygen contents may vary anywhere from a itte in excess of the contents of air up to the full strength of the oxygen supply available. In starting up for instance, I prefer to begin with an air blast and then to gradually enrich this by substituting oxygen for the air until the current has become pure oxygen or has reached such other degree of enrichment-as is desired for the operation being conducted.

The fact that the descending column of material is highly heated due to its absorption of two-thirds of the heat of the fuel prior to its entrance into the fusion zone,

rings the material so much nearer to the point of fusion that upon entering the zone where the other third of the heat of the carbon is generated, fusion is much more rapid and .this increase in rapidity of fusion is still further increased by the higher flame temperature which is induced when oxygen or air enriched with oxygen is supplied through the lower tuyere or tuyeres.

The com lete mixing of the blast delivered through the auxiliary tuyeres with the ascending gases may also be assisted by the introduction of more than one auxiliary tuyere or bank of tuyeres as already explained, the additional tuyeres being introduced at one or more successive elevations.

From the foregoing description it will be noted that the zone of fusion is removed from the sides of the furnace and the side walls are protected .from excessive'heat, and

- consequently may bemade of'cheaper materials than those ordinarily employed.

The use of fuel which is crushed or broken into small pieces, instead of the large sized pieces of coke as ordinarily used, lessens the usual s ace for the accumulation of molten ro nets and hence renders less desirable t e intermittent tapping of the furnace as at present practiced.

Furthermore, as "before noted, the pro'c ess or method as described will so increase the ra idity of fusion as to make it particulary necessary to provide other and better means for removing the molten prod ucts than the present intermittent tapping. This may be accomplished byproviding suitable channels at the lower part of the furnace which permits. continuous flow of the molten material from the lower portion of the furnace while tapping the blast. In this connection the channel 18 shown at the right hand portion of Fig. 1 will provide an exit for the heavier metal, while the channel 19 at the lower left hand ortion of Fig. 1 will provide an outlet or the lighter molten material or slag. These channels connect-with overflow spouts which are indicated respectively at 20 and 21.

The continuous flow of the molten metal and the slag will maintain the walls of 'the channels through which they flow in sufficiently heated condition so that their contents witl not become chilled. However, in order to provide for the heating of the channels in the event of irregularities or when the molten metal and the slag are insufficient to heat the channels and in order to initially heat the channels when the furnace is started, I prefer to provide a suitable heating means for the aforesaid channels. This heating means may assume any suitable or desired form, such as providing an arrangement forsending an electric current through the molten material or through a resistor provided along the bottom or side walls of the ducts by which the molten metal and slag discharges from the furnace. This resistor is made of a suitable material which conducts the electric current when cold but which will generate suflicient heat when the current is passed through the same.

An arrangement which will answer the purpose is illustrated in Fig. 1 of the, draw' ings in which a resistor element 22 extends beneath and forms a part of the floor of the furnace as well as of the. ducts through which the molten metal and slag may discharge. Associated with the resistance material are electrodes 25 and 26, by means of which current may be introduced through the resistance material. Auxiliary electrodes 27 and 28 are shown, which may be used in addition to the eectrodes before mentioned, or if desired, merely to heat portions of the resistance material, suitable combinations of electrodes may be made.

A particularly desirable construction for accomplishing the purpose of heating the outlet ducts for the furnace'is described and application filed by myoverbalanced the advantages of such fuels. Since "these difficulties are mainly due to p t conditions affecting penetration, and to tie chilling effect of in ection upon the solid fuel, es ecially when oil or powdered coal are use the open interstices and the diminution of nitrogen secured by my process makes it now possible to evade such difliculties and to utilize all such fuels freely.

This may be accomplished by introducin a fluid fuel, that is a liquid or gaseous fue or a finely pulverized fuel such as owdered coal at substantially the place within the furnace where the lower blast is introduced. In fact, the fluid or pulverulent fuel may be introduced along with the blast of air and to indicate this I have shown a tube 30 which extends within the tuyr and is supplied with the fluid or pulverulent fuel and suitable means of ressure injection (not indicated herewith connects with the pipe 31 within the tu yere. Each tuyere employed is equipped with such a conduit and injector.

It may be explained that the injectable fuels to which I refer constitute a wellunderstood and clearly defined class distinguished by having the peculiar qualities necessary for combustion within the interstices of a blast furnace column.

I Such fuel to be injectable must either be gaseous or be liquid or be a solid powdered finely. They must thus be capable of being scattered by the injection force into liquid globules or solid particles, which are small enough to be carried by the injection current through the fine interstices of a blast furnace column and to mix with the blast and to be consumed quickly by virtue of their small size, before choking these interstices.

For convenience, therefore, I shall refer to all such fuels as injectable fuel and shall distinguish between the two kinds of injectable fuels by referring to the first as gaseous fuels and to the second as nongaseous injectable fuels.

By any of the well-known means such as those indicated, the blast and the injectable fuel are introduced into the furnace at any suitable point. This preferably, as previously explained, will be substantially at the surface of contact or within the fuel mass sufliciently near to the contact for the heat and gases to reach the material efiectively.

Under such circumstances, the fluid or powdered fuel will be burned preferentially to the solid fuel and not enough blast is admitted to burn the solid fuel. The sole function of the solid fuel in this case is to maintain an open passageway for the gases which passageway is furnished by the open interstices of the fuel and its non-adherence to the pasty material along the contact. By

this passageway, the gases pass above the through a pipe 31 whichpasty zone (when. this exists) and. there escape into the more open interstices of the material column.

The solid fuel within the zone of combustion is maintained in the white hot condition necessary for the above pu topermit pro r combustion of t e injectable fuel, not y its own combustion but by contact with the preheated descendingmaterial and the flame of the injectable fuel.

The initial formin of-carbon monoxide within the zone of fusion and the subsequent formation of carbon dioxide as previously explained take place in the same fashion when the fluid or pulverulent fuel is used.

In the use of injectable fuel, the introduction of oxygen through the lower tuyres or the introduction of air enriched by oxygen, is of great benefit due to the great reduction in the volume and velocity of gases to be passed and further in the attainment of a higher flame tem rature in the zone of fusion. In fact by e imina-ting most of the nitrogen and using suflicient pressure, the reduced volume of gases can in many cases be forced through the pasty zone in the material without any aid such as is afforded by the column of solid fuel and in other cases it can be forced through with the aid of a reduced amount of solid fuel when the latter is introduced as a part of the mixture composing the furnace charge or as alternating layers with the material.

In order to maintain the proper position of the surface of contact between the descending column of solid fuel and the ma terial column when fluid or pulverulent fuel is burned without consuming the solid fuel, the column of solid fuel must descend at a uniform rate which fixes the position of equilibrium for the contact surface. The mobility of the grains in the column of solid fuel makes it possible to discharge this column at any convenient point near the base of the furnace so as to remove a suflicient quantity descent.

This is indicated .invFig. 2 of the drawings where one or more inclined water coiled pipes or conduits such as indicated at 32 are shown. Such conduits as that indicated at 32 may be placed along the side of the furnace at suitable intervals and means are provided such as the slide valves 31, which will control the passage of the solid fuel through the pipes 32. Any suitable means for removing and regulating the flow of the fuel drawn from the pipes 32 may be provided, for example, a screw conveyor 33 as indicated.

By the improved process which has just been described the blast furnace becomes applicable to novel uses among which is the production of calcium carbide. In producing calcium carbide the same arrangement to maintain the required uniform ses and of the separate descending contacting -columns ma be employed. The molten carbide will e discharged at the bottom of the furnace in the same manner as previously described.

Having described my invention, I claim, 1. The'method-of operating a blast furnace which consists in so supplying the macrushed so that its particles have less average size than those of the column of material, and supplyin an oxidizing blast.

3. The method 0 operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, supplying an oxidizing blast in the lower portion of the furnace, and supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducing or neutral atmosphere is necessary.

4. The method of operating a blast furnace which consists in so supplying-the material to be treated and the solid fuel, that they will form separate descending contacting columns, supplying a blast of oxygen or air enriched with'oxygen in thelower portion of the furnace, and supplying an auxiliary blast of oxygen or air enriched with oxygen within the column of material above the zone wherein a reducing or neutral atmosphere is necessary.

' 5. The method of operatin a blast furnace which consistsin so supp l ing the material to be treated and the so id fuel, that theywill form so arate descending cont-acting columns, an sup lying an oxidizing blast, substantially at t e surface of contact between said columns.

6. The method of. operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, and supplying a blast whose oxygen content exceeds that of air, substantially at the surface of contact between said columns.

7. The method ofoperating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, and supplying an oxidizing blast within the fuel mass suificiently near the surface of contact between said columns for the heat and gases of combustion to escape to said surface.

8. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, supplying an oxidizing blast in the lower portion of the furnace, and supplying an auxiliary oxidizing blast within the column of material above the zone of fusion.

9. The method of operating a blast furnace which consists in so suppl ing the material to be treated and the so id fuel,'that they will form separate descendinglcontacting columns, using fuel which as been crushed so that its particles have less average size than those of the column of material, supplyin an oxidizing blast in the lower portion 0 the furnace, and supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducing or neutral atmosphere is necessary.

10. The method of operatin a blast fur nace which consists in so supp ying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using. fuel which will not so agglomerate under heat as to impair the mobility of its particles and which has been crushed so that its particles have less average size than those of the column of material, supplying an oxidizing blast in the lower portion of the furnace, and supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducing or neutral atmosphere is necessary.

11. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which will not so agglomerate under heat as to impair the mobility of its particles, supplying an oxidizing blast in the lower portion of the furnace, and supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducing or neutral at mosphere is necessary.

12.: The method of operatin a blast furnace which consists in so supp ying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which will not so agglomerate under heat as to impair the movability of its particles and which has been crushed so that its particles have less average size than those of the column of mater al, sup lying a blast whose oxygen content excee s that of air in the Iowa portionof the furnace, and supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducing 'or neutral atmosphere is necessary.

13. The method of operatin a blast furnace which consists in so supp yin the material to be treated and the solid uel, that they will form separate descendinglcontacting columns, using fuel whlch as been crushed so that its particles have less average size than those of the column of material, and supplying an oxidizing blast, substantially at the surface of contact between said columns.

14. The method of operating a metallurgical furnace which consists in supplying it with material to be treated, in subjecting this material to chemical reaction and fusion and in removing two molten products by continuous flow through the same tap and electrically heating the channel of the tap when required by utilizing the most suitable one of these products as a resistor in the form of a permanently retained pool.

15. The method of operating a metallurgical furnace which consists in supplying it with material to be treated, in subjecting this material to chemical reaction and fusion and in removing the molten product by continuous flow through the channel of a tap over a permanent elongated pool of molten metal occupying the bottom of said channel and in heating said metal pool by passing an electric current through it lengthwise between the inside and the outside of the furnace.

16. The method ofoperating a blast furnace which consists in supplying it with material to be treated together with fuel and a blast, and in removing the molten roducts continuously by causing them to co ect and fiow to their outlets within a contracted channel upon the hearth bottom and to pass through the furnace walls in channels also contracted and in electrically heating the stream thus contracted in cross section b utilizing the most suitable one of said pro ucts as a resistor in the form of a 011 permanently retained in the bottom of the entire channel.

17. The method of operating a blast furnace which consists in supplying it with material to be treated together wlth fuel and a blast and removing two molten products by continuous flow through the same tap and electrically heating the channel of the ta when required by utilizing the most suitable one of these products as a resistor in the form of a permanently retained pool.

18. The method of operatin a blast furnace which consists in supp ying it with material to be treated together with fuel and a blast whose oxygen content exceeds that of air and removing two molten products by continuous flow through the same tap and electircally heating the channel of the tap when required by utilizing the most suitable one of these products as a resistor in the form of a ermanentl retained pool.

19. The metho of operati a blast furnace which consists in so supp IZing thematerial to be treated andthe so 'd fuel, that they will form separate descending contacting columns, supplying an oxidizing blast in the lower portion of the furnace, su plying an auxiliary oxidizing blast withm the column of material above the zone of fusion, and removing one or more of the molten products by continuous flow through a tap or taps, the channels of which are heated when required by passing an electric current through a resistor provided in or beneath or alongside such channel.

20. The method of operatin a blast furnace which consists in so supp ying the material to be treated and the solid fuel, that they will form separate descending contacting columns, supplyin an oxidizing blast in the lower ortion 0% the furnace so controlling said last as to form CO and burning the CO to CO by supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducing or neutral atmosphere is necessary.

21 The method of operating a blast furnace which consists in supplying to the furnace the material to be treated together with solid fuel, and supplying a blast whose oxygen content exceeds that of air and a nongaseous injectable fuel.

22. The method of operating a blast furnace which consists in supplying to the furnace the material to be treated, and supplying a blast whose oxygen content exceeds that of air and a nongaseous injectable fuel.

23. The method of operating a blast furnace which consists in supplying to the furnace the material to be treated, supplying in the lower part of the furnace a blast whose oxygen content exceeds that of air and a nongaseous injectable fuel, and supplying an auxiliary oxidizing blast above the zone wherein'a reducing or neutral atmosphere is neoemary. I

24. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, and supplying an oxidizing blast substantially at the surface of contact between said columns and an injectable fuel.

25. The method of operatin a blast furnace which consists in so supp yin the material to be treated and the solid uel, that they will form separate descending contacting columns, supplying an oxidizingblast 1n the lower portion of the furnace with injectable fuel, supplying an auxiliary oxidizing blast witlun the column of material above the zone of fusion,

and maintaining the descent of the fuel column by drawing fuel terial to be treated and the solid fuel, that they will form separate descending contacting columns, supplying an oxidizing blast together with injectable fuel, regulating the blast to a quantity sufficient to burn only the injectable fuel and maintaining the descent of the fuel column by drawing fuel out of the furnace from the lower part of the column.

27. The method of operating a blast furnace which consists in supplying to the furnace the material to be treated together with solid fuel, supplying a. blast whose oxygen content exceeds that of air, together with injectable fuel, regulating the blast to a quantity sufiicient to burn only the injectable fuel and maintaining the descent of the fuel column by drawing fuel out of the furnace from the lower part of the column.

28. The method of operatin a blast furnace which consists in so supp ying the material to be treated and the solid fuel, that they will form se rate descending contacting columns, an supplying an oxidizing blast, within the fuel mass sufficiently near the surface of contact between said columns for the heat and gases of combustion to escape to said surface, with injectable fuel.

29. The method of operating a blast furnace which consists in so supp yin the material to be treated and the solid uel, that they will form separate descending contacting columns, using fuel which has been crushed so that its particles have less average size than those ofl the column of material, supplying an oxidizing blast in the lower portion of the furnace, substantiall at the surface of contact between said co umns, with injectable fuel, and supplying an auxiliary oxidizing blast within the column of material above the zone wherein a reducin or neutral atmosphere is necessary.

30. T e method of operating a blast furnace which consists in supplying to the furnace the material to be treated together with solidfuel, and supplying a blast whose oxygen content exceeds that of air and pulverulent fuel.

31. The method of operating a blast furnace which consists in so supp mg the material to be treated and the so 'd fuel, that they will form separate descending contacting columns, and sup lying an oxidizing blast and pulverulent el.

32. The method of operating a blast furnace which consists in so supp in the material to be treated and the sofid they will form separate descendinglcontacting columns, using fuel which as been crushed so that its particles have less average size than those of the column of mateuel, that s i '7 rial and sup ying a blast whose ogygen contentexceed s that of air, substantially at the surface of contact between said columns.

33. The method of operat' a blast furnace which consists in so sup 1yin the material to be treated and the so 'd e1, that they will form separate descending contacting columns, using fuel which will not soaglomerate under heat as to impair the mobil- 1ty of its particles, supplying an oxidizin blast, and introducing under pressure with or near the blast an injectable fuel. o v

34. The method of operating a blast furnace which consists in so suppl 'ng the material to be treated and the'soli d fuel, that they will. form separate descendin contacting columns, using 'fuel which wi not so agglomerate under heat as to impair the mobility of its particles, supplying an oxidizing blast substantially at the surface of contact between said columns, and introducing under pressure with or near the blast an injectable fuel.

35. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, usingfuel which will not so agglomerate under heat as to impair the mobility of its particles, supplying a blast whose oxygen content exceeds that of air, and introducing under pressure with or near the blast an injectable fuel.

36. The method of operating a blast furnace which consists in so suppl ing the material to be treated and the so id fuel, that they will form separate descending contacting columns, using fuel which will not so' agglomerate under heat as to impair the mobility of it's particles, and supplying a blast whose oxygen content exceeds that of air and an injectable fuel. I

37. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descendin contacting columns, using fuel which wifi not so agglomerate under heat as to impair the mobility of its particles, and supplying a blast whose oxygen content exceeds that of air in the lower portion-of the furnace,

39. The method of operating a blast furnace which consists in so) supplying the anaterial to be treated and the solid fuel,

that they will form separate descending contactin columns, using fuel which has been crus ed so that its particles have less average size than those of the column of material, supplying an oxidizing blast in the lower portion of the' furnace substantially at the surface of contact between said columns, and supplying an injectable fuel.

40. The method of operat-in a blast furnace which consists in so supp ying material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which has been crushe so that its particles have less average size than those of the column of material, and

whose within the column of material above the supplying a blast whose oxygen content exceeds that of air in the lower portion of the furnace substantiall at the surface of con- ;act between said co umns and an injectable uel.

41. The method of operating a blastfurnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, supplying a blast whose oxygen content exceeds that of air in the lower portion of the furnace socontrolling said blast as to form CO and burning the CO to CO by supplying an auxiliary blast oxygen content exceeds that of air zone of fusion.

42. The method of operating a blast furnace which consists in so suppl 'ng the material to be treated and the so id fuel,

that they will form separate descending contacting columns, supp ying an oxidizing blast in the lower portion of the furnace substantially at the surface of contact between said columns so controlling said blast as to form CO and burning the CO to CO by supplying an auxiliary oxidizing blast within the column of material above the a zone of fusion.

43. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which has been crushed so that its particles have less average size than those of the column of material, supplying an oxidizing blast in the lower portion of the furnace, and supplying an auxiliary oxidizing blast within the column of material at a point above the first mentioned blast.

44. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contactin columns, using fuel which has been crus ed so that its particles have less average size than those of the column of material, supplying an oxidizing blast in and supplying an auxiliary within the column of matepoint above the first mentioned contacting columns, using fuel which wi 1' not so agglomerate under heat as to impair the mobllity of its particles, supplyin an oxidizing blast in the lower portion 0 the furnace with an injectable fuel, so controlling said blast as to form CO and burning the CO to CO by supplying an auxiliary oxidizing blast within the column of material abovethe zone of fusion.

46. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descendin contacting columns, using fuel which wifi not so agglomerate under heat as to impair the mobility of its particles, supplyin an oxidizing blast in the lower portion 0 the furnace substantiall at the surface of contact between said co umns with an injectable fuel, so controlling said blast as to form CO and burning the CO to CO by supplying an auxiliary oxidizing blast within the column of material above the zone of fusion.

47. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which will not so agglomerate under heat as to impair the mobility of its particles, supplying a blast whose oxygen content exceeds that of air in the lower portion of the furnace substantially at the surface of contact between said columns with an injectable fuel, and supplying an auxiliary oxidizing blast within the column of material above the zone of fusion.

48. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which will not so aggolomerate under heat as to impair the mobility of its particles, supplyin an oxidizing blast in the lower portion 0 the furnace substantially at the surface of con tact between said columns with an injectable fuel, and supplying an auxiliary oxidizing blast within the column of material above the first mentioned blast.

49. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descendin contacting columns, using fuel which wifi not so agglomerate under heat as to impair the mobility of its particles, supplying a blast whose oxygen content exceeds that of air in the lower portion of the furnace substantially at the surface of contact between said columns, with an injectable fuel, and supplying an auxiliary oxidizing blast within the column of material above the first mentioned blast.

50. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which Wlll not so agglomerate under heat as to impair the mobility of its particles, and supplying a blast whose oxygen content exceeds that of air in the lower portion of the furnace substantially at the surface of contact between said columns with an injectable fuel, so controlling said blast as to form CO and burning the CO to CO by supplying an auxiliary oxidizing blast within the column of material above the zone of fusion.

51. The method of operating a blast furnace which consists in so supplying the material to be treated and the solid fuel, that they will form separate descending contacting columns, using fuel which will not so agglomerate under heat as to impair the mobility of its particles, supplying an oxidizing blast in the lower portion of the furnace substantially at the surface of contactbetween said columns with injectable fuel, and maintaining the descent of the fuel column by drawing fuel out of the furnace from the lower part of the column.

52. The method of operatin a blast furnace which consists in so supp ying the material to be treated and the solid fuel, that they will form separate descendin contacting columns, us1n fuel which will not so agglomerate under eat as to impair the mobility of its particles, supplying an oxidizing blast in the lower portion of the furnace with injectable fuel, and maintaining the descent of the fuel column by drawing fuel out of the furnace from the lower part 'of the column.

53. The method of operatin a blast furnace which consists in so supp ying the material to be treated and the solid fuel, that they will form separate descending contacting columns, supplying an oxidizing blast in the lower portion of the furnace substantially at the surface of contact between said columns with injectable fuel, and maintaining the descent of the fuel column by drawing fuel out of the furnace from the lower part of the column.

54. The method of operatin a blast furnace which consists in so supp ying the material to be treated and the solid fuel, that they will form separate descending contacting columns,supp ying an oxidizing blast in thelower portion of the furnace substantially at the surface of contact between said columns with injectable fuel, supplying an auxiliary oxidizing blast within the column of material at a point above the first mentioned blast, and-maintaining the descent of the fuel column by drawing fuel out of the furnace from the lower part of the column.

55. The method of operating a metallurgical furnace which consists in supplying to the furnace the material to be treated together with solid fuel, sup lying a blast whose oxygen content excee s that of air with injectable fuel, so controlling said blast as to form CO and burning the CO to CO by supplying an auxiliary oxidizing blast within the column of material above the zone of fusion.

In testimony whereof, I hereunto aflix my signature.

EDMUND B. KIRBY. 

